Relaciones jerárquicas intra e interespecíficas entre Parablennius parvicornis y Mauligobius maderensis

Se estudia la relación de dominancia entre dos especies de peces (Parablennius parvicornis y Mauligobius maderensis) que conviven en los charcos del intermareal rocoso de las Islas Canarias. Ambas especies mostraron un patrón de jerarquía lineal basado en ataques. Se discute la jerarquía interespecífica y el cambió de rol al enfrentarse individuos de la misma especie e individuos de especies diferentes. Parablennius parvicornis mostró un comportamiento de cooperación intraespecífica y de codominancia frente a Mauligobius maderensis.It is studied the relationship of dominance between two fish species (Mauligobius maderensis and Parablennius parvicornis) which coexist in the same intertidal pools at the rocky shore of the Canary Islands. Both species showed a pattern of linear hierarchy based in attacks. It is discussed the intraspecific hierarchy and variations in the role of individuals when confronted against coespecifics or individuals of a different species. Parablennius parvicornis showed intraspecific cooperation and codominance against Mauligobius maderensis.

Exploring respiration and respiratory electron transport system (ETS) in Ulva spp.

[ES] Respiration is a key ecological index. For either individuals or communities, it can be use to assess carbon and energy, demand and expenditure as well as carbon flow rates through food webs. When combined with productivity measurements it can establish the level of metabolic balance. When combined with measurements of respiratory capacity, it can indicate physiological state. Here, we report pilot studies the metabolism of the green algae, Ulva rotundata that inhabits intertidal pools of Gran Canaria. As a starting point we used the electron transport system (ETS) to differentiate between different growing conditions in the natural environment. We suspected different levels of stress associated with these conditions and looked for the influence of this stress in the ETS measurements. This technique has been successfully applied to study bacteria, phytoplankton and zooplankton in the ocean, but it has not been used to study sessile marine macroalgae. These neritic and littoral macrophytes have major ecological and industrial importance, yet little is known about their respiratory physiology. Such knowledge would strengthen our understanding of the resources of the coastal ocean and facilitate its development and best use. Here, we modified the ETS methodology for Ulva rotundata. With this modified ETS assay we investigated the capacity of Ulva to resist anoxia. We measured respiration with optodes (Fibox 4, Presens) in the dark to the point of oxygen exhaustion and through 24 h of anoxia. Then we exposed the Ulva to light and followed the oxygen increase due to photosynthesis. We discuss here the capacity of Ulva to survive during anoxia.

Analysis of cohesion calls in "Orcinus orca" (Linnaeus, 1758)

[EN]The killer whales emit emit vocal signals to maintain group cohesion. It is assumed discrete calls are used as cohesion calls, nevertheless has not been tested if any of them could be used for other reason. Combining different stereotyped discretes calls into specific sequences increases the probability to happen a call with response. The acoustic activity of five orcas (Orcinus orca) was monitored during five different nights and distributed in three pools, leaving one orca in pool A and the rest of the group between pools B and C. Out of 4311 classified vocalizations were obtained 632 call-response sequences between different pools.